That makes finding the all-important “black box” flight data recorder infinitely more difficult, and a job perfectly suited to the U.S. Navy’s tow fish.

The 70-pound tow fish, which is formally known in true Pentagon style as Towed Pinger Locator 25, is a hydrodynamic microphone designed specifically to listen for the acoustic signal of the data and cockpit voice recorders carried aboard all commercial and military aircraft. It can track the devices to depths of 20,000 feet.